The present invention relates to a multiple spectrum image processing method, and particularly to method of and apparatus for processing image data obtained when colors of respective points on an image such as the surface of the earth are spectrum-decomposed to provide color bands of multiple channels.
A certain kind of artificial satellite, for example, takes photographs of the surface of the earth and successively transmits image data of such photographs to the earth. On the earth, it is possible to learn the states of the trees and the crops on the pictures by spectrum-decomposing an enormous amount of received image data.
As such image processing apparatus, there is commercially available an image processing program product manufactured and distributed under trade name xe2x80x9cENVIxe2x80x9d by Research Systems, Inc. in USA. Although xe2x80x9cENVIxe2x80x9d is the program product including a variety of functions concerning image processing, with respect to the image processing concerning the spectrum analysis which is related to the present invention, a spectrum plot function is described in 4-4 to 4-14 of Version 2 of user""s guide and a color synthesis and display function is described in 4-20 to 4-25.
According to the plot function of xe2x80x9cENVIxe2x80x9d, a spectrum of a spot designated by a user on the image is displayed. When the user designates a desired spectrum channel on the designated spectrum, an image of a spectrum channel is selected from image data comprised of images of multiple spectrum channels and displayed.
According to the color synthesizing function of xe2x80x9cENVIxe2x80x9d, there is obtained a color synthesized image by allocating R (Red), G (Green) and B (Blue) to images of multiple spectrum channels containing channels of visible light region and channels of infrared region. However, the user is not able to arbitrarily add weights of RGB characteristics to individual spectrum channel images. As a result, it is difficult to create a color synthesized image with a high S/N (signal-to-noise ratio) in which a user""s desired spectrum channel is emphasized. Further, the color synthesizing function of xe2x80x9cENVIxe2x80x9d does not have a function to use a color synthesized image obtained by allocating RGB for a variety of analyses.
It is an object of the present invention to provide image data processing method and apparatus in which a variety of spectrum analyses may be carried out by using a color image obtained on the basis of multiple spectrum channel images.
In order to attain the above-described object, according to the present invention, RGB are allocated to multiple channel spectrum images including a visible light region and an infrared region. An R image (hereinafter referred to as xe2x80x9cR virtual spectrum aperture imagexe2x80x9d) is obtained by adding weights of center, width and intensity characteristics of R to every spectrum channel of the portion to which R is allocated. Similarly, a G image (hereinafter referred to as xe2x80x9cG virtual spectrum aperture imagexe2x80x9d) is obtained by adding weights of center, width and intensity characteristics of G to every spectrum channel of the portion to which G is allocated. A B image (hereinafter referred to as xe2x80x9cB virtual spectrum aperture imagedxe2x80x9d) is obtained by adding weights of center, width and intensity characteristics of B to the portion to which B is allocated. A color synthesized image (hereinafter referred to as xe2x80x9cRGB imagexe2x80x9d) is obtained by synthesizing the three kinds of virtual spectrum aperture images.
When this RGB image is displayed on a display apparatus and a user draws a desired line on the displayed RGB image, spectrum groups obtained at a plurality of points comprising such line are displayed on another display area on the display apparatus. Further, when the user draws a line such that the line crosses a line on the RGB image or that the line becomes parallel to the channel direction on the displayed spectrum group, a spectrum of one point at which the lines cross each other is displayed on other display area on the display apparatus. Furthermore, when the user designates a desired point independently of the line crossing point, spectrums of two points are displayed on the same display area.